Add Author model fields to AuthorSerializer

- Imported the Author model into serializers and implemented the AuthorSerializer.

author/serializers.py

@@ -1,6 +1,9 @@
 from rest_framework import serializers
 
+from author.models import Author
+
 
 class AuthorSerializer(serializers.ModelSerializer):
-    # write your code here
-    pass
+    class Meta:
+        model = Author
+        fields = ["first_name", "last_name", "pseudonym", "age", "retired"]